不同氮添加水平对杨树根际土壤丛枝菌根真菌群落结构的影响毕业论文_生态学毕业论文

不同氮添加水平对杨树根际土壤丛枝菌根真菌群落结构的影响毕业论文

2021-04-27更新

摘 要

丛枝菌根真菌(AMF)作为陆地生态系统的重要组成部分,它可以同约莫80%的陆生植物构成AMF-植物共生体。在经济迅速发展的当代社会,氮沉降的持续增加不仅影响着大气环境,对杨树根菌土壤丛枝菌根真菌也造成一系列问题。本课题以江苏省东台试验林场杨树人工林为研究对象,选择立地条件及造林方式相同杨树林,通过人工施氮的方式模拟氮沉降,共设置五个氮添加处理,包括对照(NO)、低氮处理(N1)、中氮处理(N2)、高氮处理(N3)以及超高氮处理(N4) ,采用随机区组的设计方法,设置五种氮添加水平的给每个样地。通过采集杨树根际土壤,研究杨树根际土壤AMF群落结构的差异,以及不同氮添加水平对杨树人工林土壤AMF群落结构的影响程度和控制因素,为氮沉添加土壤丛枝菌根真菌的影响提供科学依据。结果如下:

  1. 在杨树人工林中,氮添加显著影响土壤AMF群落但具有阈值效应,中浓度氮添加有利于土壤微生物的繁殖和生存,高浓度氮添加对土壤微生物产生抑制作用。

(2)AMF OTUs序列进行分类学分析(mothur,silva数据库),将每一条优质序列与数据库进行比对,在科水平统计每个样品的AMF群落组成。不同氮添加水平下,东台杨树人工林根际土壤中存在4个目,7个科的AMF群落,80%以上的样品中有球囊霉科(Glomeraceae)、巨孢囊霉科(Gigasporaceae)、多样孢囊霉科(Diversisporaceae)和原囊霉科(Archaeosporaceae)AMF。

关键词:氮添加;杨树人工林;菌根真菌;群落结构;

Effects of Different Nitrogen Addition Levels on the Community Structure of Mycorrhizal Fungi in Soils of Poplar Rhizosphere

ABSTRACT

Arbuscular mycorrhizal fungi (AMF) are an important part of the terrestrial ecosystem and can form AMF-plant symbiont with about 80% of the terrestrial plant species. In the contemporary society with rapid economic development, the continuous increase of nitrogen deposition not only affects the atmospheric environment, but also causes a series of problems to the soil arbusculaceae fungi of poplars root fungus. In this study, poplar plantation in Dongtai experimental forest farm of Jiangsu province was taken as the research object. The site conditions and afforestation methods of poplars were selected to simulate nitrogen deposition through artificial nitrogen fertilization. A total of five nitrogen addition treatments were set up, including control (NO), low nitrogen treatment (N1), middle nitrogen treatment (N2), high nitrogen treatment (N3) and super high nitrogen treatment (N4). By collecting poplar rhizosphere soil, the difference of the AMF community structure of poplar rhizosphere soil was studied, and the influence degree and control factors of AMF community in poplar plantation soil with different nitrogen addition levels were clarified. Then it could provide scientific basis for the effect of nitrogen deposition on soil CONUS mycorrhizal fungi. The results are as follows:

1) In poplar plantations, nitrogen addition significantly affects the soil AMF community but there is a threshold effect. The middle concentration of nitrogen addition is conducive to the reproduction and survival of soil microorganisms. The high concentration of nitrogen addition has an inhibitory effect on soil microorganisms.

2) AMF OTUs sequences are classified(mothur, Silva database), and each high-quality sequence is compared with the database, and the AMF community composition of each sample is counted at the level of the family(Figure 2). At different levels of nitrogen addition, there are 4 orders and 7 families of AMF communities in the rhizosphere soil of Dongtai Poplar plantation. More than 80 % of the samples included Glameraceae, Gigasporaceae, Diverisporaceae, and Archaeosporaceae AMF.

Key words:Nitrogen deposition; Poplar plantation; Mycorrhizal fungi; Community structure;

目 录

1 前言 1

1.1 研究背景和意义 1

1.2 国内外研究概况 1

1.2.1 AMF在生态系统中的作用 2

1.2.2 影响AMF群落结构的因素 3

1.2.3 氮添加对AMF群落影响的研究现状 4

2 材料与方法 5

2.1 试验区概况 5

2.2 样地与试验设置 5

2.3 样品采集 6

2.4 样品指标测定 6

3 结果与分析 8

3.1 不同氮添加对杨树根际土壤基本理化性质的影响 8

3.2 不同氮添加水平杨树根际AMF群落结构和多样性 11

3.3 不同施氮水平杨树根际土壤AMF群落结构与环境因子的关系 14

4 讨论 16

4.1 不同氮添加对杨树根际土壤基本理化性质的影响 16

4.2 不同氮添加水平杨树根际AMF群落结构和多样性 16

4.3 不同施氮水平杨树根际土壤AMF群落结构与环境因子的关系 16

结论 17

致谢 18

参考文献 19

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